Good morning and welcome!!
I like the pattern, a cool 'twist' on rail fence!

So, on the pattern you have picked where the piecing only runs in one direction it will be very obvious if your cutting or piecing is off even just a bit. A couple threads on each cut and/or a few threads on each seam and you could quickly end up that 1/2" off. Or, 1/16th of an inch on each seam...that is pretty, um, tiny!

So, I would suggest double checking to make sure you strips are the correct width.
Suggestion. When cutting, be sure to use the same ruler for all your cuts for a quilt. Or at least the same kind/brand.

The ever elusive 1/4" seam is a pain! Most everyone on here has struggled with it at some point, so you are in good company!
One of the best suggestions I ever followed was, cut some squares, whatever size you want 2" or 3". Sew a set together, press them open and then measure the unit. If you cut 2" squares, the unit should measure 3.5". If you use 3" squares the unit should measure 5.5". If your unit measurement is off, make the necessary adjustments and try again. When you have it right, put some painters tape on the sewing machine bed to use as a seam guide. Voila!!